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<a name="Mixed_002dLanguage-Programming-1"></a>
<h2 class="chapter">6 Mixed-Language Programming</h2>
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<tr><td align="left" valign="top">&bull; <a href="Interoperability-with-C.html#Interoperability-with-C" accesskey="1">Interoperability with C</a>:</td><td>&nbsp;&nbsp;</td><td align="left" valign="top">
</td></tr>
<tr><td align="left" valign="top">&bull; <a href="GNU-Fortran-Compiler-Directives.html#GNU-Fortran-Compiler-Directives" accesskey="2">GNU Fortran Compiler Directives</a>:</td><td>&nbsp;&nbsp;</td><td align="left" valign="top">
</td></tr>
<tr><td align="left" valign="top">&bull; <a href="Non_002dFortran-Main-Program.html#Non_002dFortran-Main-Program" accesskey="3">Non-Fortran Main Program</a>:</td><td>&nbsp;&nbsp;</td><td align="left" valign="top">
</td></tr>
<tr><td align="left" valign="top">&bull; <a href="Naming-and-argument_002dpassing-conventions.html#Naming-and-argument_002dpassing-conventions" accesskey="4">Naming and argument-passing conventions</a>:</td><td>&nbsp;&nbsp;</td><td align="left" valign="top">
</td></tr>
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<p>This chapter is about mixed-language interoperability, but also
applies if you link Fortran code compiled by different compilers.  In
most cases, use of the C Binding features of the Fortran 2003 and
later standards is sufficient.
</p>
<p>For example, it is possible to mix Fortran code with C++ code as well
as C, if you declare the interface functions as <code>extern &quot;C&quot;</code> on
the C++ side and <code>BIND(C)</code> on the Fortran side, and follow the
rules for interoperability with C.  Note that you cannot manipulate
C++ class objects in Fortran or vice versa except as opaque pointers.
</p>
<p>You can use the <code>gfortran</code> command to link both Fortran and
non-Fortran code into the same program, or you can use <code>gcc</code>
or <code>g++</code> if you also add an explicit <samp>-lgfortran</samp> option
to link with the Fortran library.  If your main program is written in
C or some other language instead of Fortran, see
<a href="Non_002dFortran-Main-Program.html#Non_002dFortran-Main-Program">Non-Fortran Main Program</a>, below.
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